Oxazolidinium compounds are formed by the reaction of a halohydrin or an epoxide with a secondary amine and an aldehyde or a ketone. The oxazolidinium compounds are formed directly and do not require the reaction of a pre-formed oxazolidine with an alkylating agent. The compounds are useful as gas hydrate inhibitors in oil and gas production and transportation. The oxazolidinium compounds have the structure: where R is a saturated or unsaturated alkyl group containing from 3 to 20 carbon atoms, where R has an absence of aryl groups; R1 and R2 each independently have 1 to 20 carbon atoms, may be linear, branched or cyclic; linear, branched or cyclic groups having 1 to 20 carbon atoms substituted with alkyl groups, aryl groups, alkylaryl groups, and aryl groups substituted with alkoxy groups, and X is selected from the group consisting of chlorine, fluorine, bromine or iodine.